just got this drill and the chuck wobbles a little bit, is it defective?

Diagnosis

The Milwaukee M18 FUEL Hammer Drill (2904-20) utilizes a heavy-duty all-metal ratcheting chuck. When you notice a "wobble," it is typically one of two things: runout (the bit is not spinning on a perfect center axis) or mechanical play in the spindle assembly. In a brand-new unit, this is often caused by a misalignment between the spindle taper and the chuck seating, or a defect in the internal bearings of the gear housing. To confirm if the tool is truly defective, you must distinguish between "chuck play" and "bit runout." If the chuck housing itself moves independently of the drill body, you have a bearing or spindle failure. If the chuck is firm but the drill bit circles a wider area than the center point during rotation, the spindle is likely bent or the chuck was not pressed onto the taper squarely at the factory. A wobble exceeding 0.005 inches at the tip of a short 2-inch bit is generally considered outside of acceptable tolerances for this professional-grade tool.

How to Fix It

Since the 2904-20 is a sealed unit with a press-fit chuck, you cannot "tune" the alignment yourself without specialized industrial presses. However, follow these steps to verify the defect before seeking a replacement:

1. Select a high-precision, short-shank drill bit (preferably a 1/4" cobalt bit). Long bits naturally amplify wobble and will give you a false positive for a defect.
2. Insert the bit fully into the chuck. Ensure the bit is seated deep enough that it isn't resting on the edge of the chuck jaws.
3. Tighten the chuck firmly using the ratcheting sleeve. Do not over-torque, but ensure it is locked.
4. Place the drill on a flat, stable workbench. Hold the tool firmly and set the speed trigger to the lowest possible RPM.
5. Place a dial indicator or a steady pointer (like a needle) 1/16th of an inch from the tip of the bit.
6. Observe the rotation. If the tip of the bit moves in a visible circle (runout) while the chuck body remains stationary, the spindle is defective.
7. If the entire chuck assembly shakes or vibrates rhythmically, the internal gear transmission or main bearing is flawed.

If That Didn't Work

• Test with a different bit brand: Some low-cost bits have slightly eccentric shanks. Try a Milwaukee Shockwave or a precision machinist bit to ensure the wobble isn't coming from the accessory rather than the tool.
• Check for debris: Inspect the interior of the chuck jaws for metal shavings or plastic flash from the manufacturing process. Even a tiny piece of debris can prevent a bit from seating squarely, causing a perceived wobble.
• Verify the "Clutch" setting: Ensure the torque clutch is fully engaged. While the clutch doesn't affect the spindle's axis, a loose clutch ring can sometimes create a vibration that feels like chuck wobble during high-torque starts.
• Perform a "Dry Run" with a Test Mandrel: If you have access to a precision ground mandrel, insert it into the chuck. This removes the variable of the drill bit's own quality and tells you exactly how much runout the spindle is producing.

Heads Up

• Warranty Voidance: Do not attempt to remove the chuck using a hammer or heat. The 2904-20 chuck is a press-fit component; attempting to "straighten" it will void your 5-year power tool warranty.
• Avoid Over-tightening: Using a wrench to tighten the ratcheting chuck beyond finger-tight can actually distort the jaws, increasing the runout of the bit.
• Bearing Care: Avoid dropping the tool on its nose. The M18 FUEL series is rugged, but a direct impact to the chuck can bend the spindle, leading to the exact wobble you are experiencing.
• Exchange Window: If the tool was purchased within 30 days, request a direct exchange rather than a warranty repair. A spindle alignment issue is a fundamental manufacturing flaw that is better solved by a replacement unit than a part swap.